ABSTRACT
Objective To investigate the influence mechanism of Cordyceps sinensis (CS) on β-glycerophosphate-induced vascular smooth muscle cell (VSMC) calcification.Methods The effect of CS on VSMC cell viability was detected by CCK-8.The cellular models of rat VSMC calcification were established by treating with β-glycerophosphate (β-GP,10 mmol/L);then CS (10 mg/L),autophagy inhibitor 3-methyladenine (3-MA,5 mmol/L),and AMPK inhibitor compound C (CC,10 μmol/L) were added to the cell cultures.There were a total of 5 experiment groups:VSMC cultured in normal medium (Control),VSMC treated with β-GP,VSMC treated with β-GP and CS,VSMC treated with 3-MA,β-GP and CS,and VSMC treated with CC,β-GP and CS.The calcium nodules and calcium content were examined with alizarin red S staining and the O-cresolphthaleincomplexone method,respectively.The autophagosomes within the VSMC were observed using transmission electron microscope (TEM).Immunofluorescence showed the accumulation of microtubule-associated protein 1 light chain 3 (LC3) puncta.In addition,levels of osteogenic related proteins,autophagy related proteins,and AMPK/mTOR pathway related proteins were evaluated by Western blotting.Results CS increased the number of autophagosomes and the accumulation of LC3 puncta within VSMC.It also upregulated the protein levels of LC3 Ⅱ/LC3 Ⅰ,beclin1,α-SMA,and p-AMPK;whereas,the protein levels of Runx2 and p-mTOR,as well as calcium nodules and calcium content were reduced (all P ＜ 0.01).When the cells were pretreated with 3-MA before treating with β-GP and CS,the autophagosomes,accumulation of LC3 puncta,and protein levels of LC3 Ⅱ/LC3 Ⅰ,beclinl,and α-SMA were decreased (all P ＜ 0.01);however,the protein level of Runx2,and the calcium nodules and calcium content were increased (all P ＜ 0.01).Nevertheless,when the cells were pretreated with CC before giving β-GP and CS,the autophagosomes,the accumulation of LC3 puncta,and the expression levels of p-AMPK,LC3 Ⅱ/LC3 Ⅰ,beclin1,and α-SMA were significantly down-regulated (all P ＜ 0.01);whereas,the expression levels of Runx2 and p-mTOR,as well as calcium nodules and calcium content were increased (all P ＜ 0.01).Conclusions CS can effectively alleviate β-GP-induced VSMC calcification,which may be due to the activation of autophagy by AMPK/mTOR signaling pathway.